Iris recognition is a rising biometric identification technology and extends its application in the identity recognition field. Safe and convenient identity recognition is the difficulty of developing services for mobile terminal business. Currently, use of mobile terminals as measures for identity recognition mainly depends on password and card, which is difficult to remember, easy to steal and low in safety. In numerous identity recognition technologies, iris recognition has the highest safety and precision, and possesses the advantages such as being unique for individuals, not needing to be remembered, being unable to be stolen, having a high safety level, and so on.
In the prior art, iris imaging design generally employs fixed focus design. The user needs to voluntarily cooperate to seek a suitable iris imaging position, so that additional hardware devices such as a distance-measuring sensor, a three-color indicator light, etc. are required. There are some iris imaging systems using a stepping motor or direct-current motor to drive the lens to move back and forth so as to achieve iris autofocus and imaging, but they still need a distance-measuring sensor to measure the distance; moreover, the stepping motor or direct-current motor has high power consumption due to a large volume. These all lead to great increase in the volume of the iris imaging system, extension in recognition speed, and poor user experience. It is impossible to miniaturize and integrate it into mobile terminals which are widely required.